As an exhaust gas purification catalyst provided in an exhaust passage of an internal combustion engine, there has been developed heretofore an electric heating catalyst (which will be hereinafter referred to as “EHC”), in which a catalyst is heated by a heater element that generates heat by supply of electric current.
There has been known an EHC having a structure in which two electrodes are connected to the side surface (outer circumferential surface) of a heater element in such a way as to be opposed to each other (see, e.g. Patent Document 1). In this structure, current flows between the electrodes through the heater element, whereby the heater element generates heat.